Kanzi the bonobo could play pretend, study finds

A study published in Science reports that Kanzi, a bonobo who understood English, tracked imaginary juice and grapes during controlled tests, indicating he could follow human-created pretend scenarios.

Researchers report experimental evidence that a bonobo named Kanzi could follow human-created pretend scenarios. The work, published in Science, tested whether Kanzi could track imaginary objects during simple tasks. Kanzi had been trained to point to real juice and could understand English cues, which the team used in controlled trials. The finding builds on anecdotal reports of pretend behaviors in great apes but was produced under experimental conditions. Key findings: - The study was published in the journal Science and used Kanzi, a bonobo who understood English, as the subject. - In a test where experimenters pretended to pour juice into empty cups, Kanzi identified the location of the pretend juice correctly on 68% of trials. - In a control test with one real cup of juice and one empty cup that was the target of pretend pouring, Kanzi chose the real cup 77.8% of the time, indicating he could distinguish real from imaginary juice. - A follow-up test with a pretend grape produced a correct identification rate of 68.9%. - The research involved only one individual subject, and Kanzi died in March 2025; the authors note this as a limitation. Summary: The experiments provide direct, controlled evidence that at least one bonobo could track imagined objects presented by humans, which researchers say aligns with anecdotal observations of pretend behavior in great apes. The team hopes to explore whether other great apes show the same capacity, and further testing across individuals is needed.